S/PDIF Battle: Mutec, Singxer, Lynx, Rednet, Eitr, Et Al.

I am a born skeptic. Until I heard a properly good amplifier with legit headphones, I didn’t think they were necessary. Until I heard a good R-2R DAC against a theoretically-good Delta-Sigma DAC, I thought all DACs sounded essentially the same.

As I’ve progressed in my audiophilia, I am left with few frontiers to conquer when it comes to convincing myself to spend money on audio products. Cables and USB to S/PDIF converters are were perhaps the last bastion for me.

Note that I won’t be talking a lot about specifics for any of the S/PDIF converters here. There’s ample information on their websites about technical data, features, and prices. If I listed all of the information here, this entry would become far too long. Do your research and come back here for one user’s opinion.

Gustard U12, Audio-GD DI-2014 & DI-U8, CIAudio Transient MKII

I started my journey into S/PDIF conversion with some common converters. The Gustard U12 was hardly an improvement over the USB in my DACs, and in fact seemed worse in a few cases. The Audio-GD DI-2014 seemed like maybe it was slightly better, but it was hard to definitively say I was hearing any benefits. The Audio-GD DI-U8 felt like a slight improvement over that. The CIAudio Transient MKII was only slightly better than the DI-U8 but started getting into audible territory–when I switched back to the DAC’s USB input, I perceived a difference more than heard one.

I breeze right by all of those converters because they had one thing in common: while I could convince myself that I was hearing some slight improvements in my (at the time) Audio-GD Master-11, I didn’t ever feel they were worth the money to keep in the chain. The simple USB gizmo known as the UpTone Regen (pre “Iso” generation) did as much for the Amanero Combo384 in that DAC as any S/PDIF converter I tried.

The journey continued. I eventually discovered how much I love tubes, and my beloved Master-11 went to a new home. I also found that I really enjoyed the sound of non-oversampling DACs after a few false starts in that direction, and ultimately found MHDT Labs. They make non-oversampling tube DACs with R-2R chips. I love the heck out of them, and they also benefit quite a bit from good S/PDIF input over USB. After finding MHDT, I embarked again on my journey of S/PDIF conversion.

Mutec MC-3+USB & 1.2

Not to be put off from spending too much money, I heard about a couple of pro audio contenders: The Mutec MC-3+ Smart Clock USB and Mutec MC-1.2. The MC-3+USB is a re-clocker and USB interface rife with features (many that I’ll never use), and the MC-1.2 is the little brother that doesn’t re-clock the incoming signal.

When I first plugged my system (now a modded MHDT Labs Atlantis going to the ampsandsound Mogwai amplifier) into the Mutec MC-3+USB, my smug look born of my belief that I’d hear little difference was wiped away immediately.

The Mutec MC-3+USB was the first USB to S/PDIF converter that I could unequivocally state audibly improved the sound of my system. Everything got smoother, more effortless, more expansive, and extension and separation seemed to improve. The effect is still subtle, but it is on the order of two completely different DACs rather than something extremely minor. Update: Note that there has been quite a bit of discussion over this converter. It seems that different firmware versions yield audibly different results, which can be a bad thing. Some firmware imparts minimal coloration, while other firmware changes the sound (not necessarily improves it).

The Mutec MC-1.2 was also very good for the price, but simply can’t satisfy after hearing its big brother. It’s a bit less smooth, a little swooshy and airy at the top in comparison, and less hard hitting. It’s better than the previous crop of converters I tried out, but can’t measure up against the much more expensive MC-3+USB after you’ve heard it.

Thus began a spending spree to find the the right S/PDIF converter. I wanted to find the best at the top of my price range as well as the most practical devices that I’d be happy with.

I grabbed some non-USB solutions first. The ESI Juli@ XTe, Lynx E22, and Focusrite Rednet 3 were among the contenders.

ESI Juli@ XTe

The ESI is in the realm of the mid-priced USB S/PDIF converters overall. It lacked what I’ve come to understand as digital hash (swooshy feeling to the sound, almost like you’re rubbing together dry napkins inaudibly while listening to music). But it also didn’t work wonders with the soundstage or separation, and was outdone by the Mutec MC-1.2 in this regard. It lends a slight murkiness to the overall picture, like a very thin veil that makes everything pleasant but not detailed. It’s better than just about any integrated USB solution and does fix the USB swoosh, though.

Lynx E22 / AES16e

Next up was the Lynx E22. This is a no-nonsense PCI Express card that is built for pro audio. No digital hash, no glare, very good dynamics and separation. It’s a touch less smooth than the Mutec MC-3+USB in my setup and with that firmware.

Update: I discovered that I originally failed to change the E22’s mode from AES to S/PDIF mode. It still worked with my DAC, but wasn’t doing anyone any favors. I also had recently adjusted my tube choice to account for the sound of the Mutec (very smooth). After adjusting for user error with the jumpers and changing out the tubes in my equipment to complement the Lynx instead, I discovered an amazing solution in the Lynx E22 (and AES16e).

Dynamic, clean, excellent staging. If I have one complaint it’s that it is a little dry in presentation. If I have another it’s that it costs a lot to use it just as an S/PDIF converter when you aren’t using all of its functionality.

Focusrite Rednet 3

Now comes the Focusrite Rednet 3. It’s a Dante-based converter intended for professional audio use. It is the first audio-over-IP device I’ve tried. I directly connected it to my computer’s ethernet port. Immediately, I was faced with issues. It doesn’t work out of the box at all because the installed firmware doesn’t work with the latest software. So I had to go download the firmware update and install it. Twice, for good measure, because the Rednet software doesn’t trust you and does it again after the device is detected for the first time.

Then it started working, albeit with the caveat that all music must be piped to it at the same sample rate. And my was I impressed. The Rednet 3 sounds absolutely outstanding. Despite the bad taste in my mouth from the early frustrations, it might be the best of the bunch in overall sound quality. I did start to experience some occasional dropouts, but I eventually tracked it down to JRiver because foobar2000 wasn’t causing the issue, so I switched media players.

Weaknesses? Well, it’s not user friendly. It can’t change sample rates on the fly. It’s a double rack height massive red behemoth. And, it takes over your ethernet port unless you buy a separate card for it or use wireless. Plus, it ain’t cheap. The reward for all of the sacrifices is an amazing sound. No digital hash, incredible extension, wonderful dynamics, top notch separation.

So I sold it.

What? Yeah, I couldn’t deal with the size or redness. Am I an idiot? Probably. I also didn’t feel like spending another $100 to get AES output since it doesn’t come with breakout cables, nor did I want to spend the money for a good internal ethernet card. Will I go back? If they ever make a Dante-based Rednet device that sounds just as good and is intended for personal audio use (and is much smaller), absolutely.

I settled in at home for a while with the Lynx E22 going to the Mutec MC-3+USB as a re-clocker (eventually deciding the Mutec wasn’t helping enough to keep it, so I dropped that out of the setup). Much smaller footprint than the Rednet and it sounds nearly as good to me as the Rednet 3 alone.

All of this madness at home made me miss the devices at work, so I experimented with some more economical options rather than using a four-figure device there.

Singxer F-1 & SU-1

That led me to try the Singxer F-1, which uses the new XMOS XU208 USB converter as opposed to the XMOS U8 in many of the other devices I’ve tried (including, I believe, in the Mutec).

It garnered significant praise over at Head-Fi, and I found that it was indeed warranted. This sub-$200 device was nearly as good as the Mutec MC-1.2 at less than half the price.

It shares some of the weaknesses of other USB devices in a similar class though, with that slightly swooshy USB sound that I’ve developed an aversion to. People have solved that with all sorts of UpTone Regens, cables, linear PSUs, and other decrapifiers. I’m not willing to go to such great lengths (pun intended) to clean up a USB chain. So off it went to a new owner.

But I was intrigued by the performance to price ratio, so I ordered a Singxer SU-1. It uses the same converter but has more outputs and a Talema transformer inside.

I was not disappointed with the results.

The Singxer SU-1 is very good, especially with consideration for the price before the Eitr came along. It’s superior to the Mutec MC-1.2 and all other USB to S/PDIF converters I’ve tried apart from the Mutec MC-3+ Smart Clock USB (Update: See Schiit Eitr below). In my “modest” (MHDT Labs Canary to a Garage1217 Project Sunrise III) work setup, its not discernibly inferior to the Mutec at all. Differences can be heard in my home setup, but they are hard to hear.

Schiit Eitr

It’s the middle of 2017, and Schiit has to take a dump all over the industry and introduce a USB to S/PDIF converter of their own.

Let me be clear about my position on Schiit before I begin: I think their name is a load of childish marketing and most of their products are too treble-intensive for me to listen to for more than a few minutes. The only other products of theirs that I’ve kept are the Sys (allows you to quickly switch between devices with RCA connections) and Wyrd (which objectively corrected some USB connectivity issues I was having at work with some devices).

So they come up with USB Gen 5 and pack it in a box the size of the Magi/Modi/Wyrd/Sys then pop a price tag on it. It does one thing: converts USB to S/PDIF on its single RCA output.

The price tag didn’t inspire much confidence in it being a worthy solution. $179 and from a USA company? Probably a piece of shit. Pun always intended.

Obviously, the second I saw that it was announced and available on their website, I ordered it. Then I briefly read what it could do, then I went to Super Best Audio Friends to see if anyone had heard it. Then I waited. Like a day, because I live an hour south of them. And I chuckled when I realized that I just bought a Shit Eater.

Listening impressions?

Using an MHDT Labs Atlantis+ or Orchid, it’s astonishing how audibly superior the Schiit Eitr is to common USB solutions.

For something at the Eitr’s price point, I was expecting something roughly as capable of ditching the USB swoosh as the ESI Juli@ XTe.

I was wrong.

I was guilty of being tricked into believing the Mutec MC3+USB was utterly amazeballs because it made audible differences to the sound.

What I eventually realized in comparisons with the likes of the Rednet 3 and Lynx E22 (especially after I tried the latter with AES or remembered to switch it properly to S/PDIF mode for all my other DACs) is that the Mutec was not neutral. Different, yes. Great–to my ears–yes. But after experiencing proper neutrality with the Lynx and Rednet I now perceive “different” as what it is rather than “better.”

The Schiit Eitr doesn’t make the sound “different.” The ESI Juli@ XTe is very neutral and does a great job of not coloring the sound. When compared directly to a Lynx E22, the Lynx (sorry for this overused expression) lifts a veil. Clarity, detail, and dynamics all improve with the Lynx above the ESI without changing the color of the music in any way.

That’s what the Eitr does. Switching between the ESI to the Schiit Eitr removes a bit of blurriness you didn’t realize was there. It doesn’t accentuate anything or color anything, it just allows the music to flow unfettered from the computer to your DAC.

It may very well be the best USB solution I’ve ever heard. No hint of the digital hash or swoosh I associate with USB. Beautifully black background. Effortless.

I now have one for home, one for work, and bought one for a friend. 3 for the price of 1 Lynx (which is arguably still better, but complete overkill for the slight benefit).

Faults? There are a few, yes. I had issues getting the driver to recognize I had the device plugged in and wasn’t having a wonderful time getting it installed. Luckily, the MHDT DACs use the same USB processors (CM6631A) and turning those on with USB got the drivers installed. I’m guessing it had to do with lingering drivers for the MHDT. People have also complained about getting it to work with iPads/iPods and other phones and tablets, though some seem to have it working fine.

Are you done rambling yet?

So, this wandering sojourn has led me to a promised land. My wallet suffered in the process, but I’ve sated my curiosity and found some incredible devices.

Here’s my subjective ranking of the various devices I’ve spent a fair amount of time with when used alone (adding more into the chain just confuses matters):

Focusrite Rednet 3

Lynx E22 | Lynx AES16e

Schiit Eitr | Mutec MC-3+ Smart Clock USB

Singxer SU-1

ESI Juli@ XTe

Mutec MC-1.2

CI Audio Transient MKII

Singxer F-1

Audio-GD DIU8

Audio-GD DI-2014

Gustard U12

Favorite S/PDIF Device

Overall: Lynx E22/AES16e

Truly neutral presentation without coloration. This is much easier to use than the Rednet that it trades blows with as the top contender, but the Rednet is just too much of a hassle to recommend it to anyone in a non-professional situation. I use the AES16e as my primary source still as of January 2018.

USB: Schiit Eitr

Cures the digital hash/swoosh of USB, is no-nonsense, and it’s pretty inexpensive. It doesn’t do DSD or exotic sample rates (greater than 192kHz), but it does its one trick very well. I have not heard the latest Mutec firmware to confirm whether it’s as good as or better than the MC-3+USB, but it’s on the same level and way cheaper.

Best Bang-for-the-Buck S/PDIF Device

Schiit Eitr

Nothing comes close to the value of the Schiit Eitr. The other USB devices might as well not exist if all you’re after is S/PDIF conversion. You have to spend more than 4x the price to get something better (Lynx E22 at $700 + breakout cable + AES->S/PDIF cable).

As a new owner of Audio GD’s NOS-11 I have been wondering how SU-1 with I2S output to NOS-11 would match against those higher ranked gear?
It’s been said those Audio GD gear sounds best using I2S so if I would get, say Mutec MC3+, I would lose that I2S output option but probably gain something with reclocking of Mutec.
NOS-11 does not have AES input while Mutec or AOIP devices are mostly missing I2S output.

I guess going first with Intona USB isolator would be a nice start upgrading source signal. Ahh, what a mindfuck.

Thank you for your opinion on the issue. Ignoring Intona sounds interesting since it has got lots of recommendation, even with chained usb gear.
I was leaning strong towards i2s output, this just encourages my thoughts. I’ll just get SU-1 and see/hear what happens next 😉

While I’m already here, do you have any experience regarding cables in i2s use? Is it worth investing any pricier cable than regular HDMI-cable?

I really enjoyed your writeup. I have an Aurender N100h server and it has only USB output. I have been using the Mutec MC-3+ USB for about a year and I agree that it is a great product. About 2 months ago, after reading your analysis, I bought a Singxer F-1 to test against the Mutec. I am having a hard time telling them apart. They’re so close, the F-1 seems like a real bargain. Even with Stax headphones, I really can’t tell them apart.

I’ve personally tried, eitr, su1, f1, di-2014, diu8, lynx aes16e which is all on your list, and I agree with all your impressions.
This list has helped me time and time again, because you keep updating it. Thank you for the hard work put into this, it’s appreciated.

Hi.It is good.Also I don’t like crazy usb cleaner tails.
Esi juli pci or pci-e cards are very famous for diy world.They power the boards with clean power and it makes real difference.I hope you can try this to add this comparison..This can give new order to esi juli in your list..

I also have singxer f1.And I am powering its Second power with battery.
I am really tired from searching to find an usb spdif converter and I am also using a nos dac.
You are looking to a forum and they are saying ‘oo it is very good it has very low jitter 5.6ps’
After 6 month you are looking on same forum”they are saying it is clearly better than singxer f1.It is matrix spdif2..
And then you are looking on other forum they are saying Schiit Eitr..
And you are looking an other forum.They are saying BADA is The Best.
And you are looking other forums.They are saying Audiophilleo with pure power is The Best..

It seems like some kind of new marketing maybe..

I don’t see any valid point why one of them better than other..
Jitter isn’t enough..
Isolation For I2s lines isn’t enough..
Output section discrete isn’t enough..
Ferrit on isolation chips isn’t enough..

So we will buy these things and we will sell in 5month.And we will buy another..
This is very strange.
Science is moving very fast I think..(I don’t think so..).
Like nobody knowing enginering and applying their tricks on their products and they are saying we improve things much better..What The fuck!!Why didn’t you apply it 5 mounths ago..Do not tell me The input chip is improved!!
They don’t wait enough to evaluate their products…

If you are reading this.Do not buy anything based on any forum!!

I can’t afford Lynx or Rme card.But I am very pleased to see professional cards on your list on upper order..

Thanks and last thing I am connecting one ‘X’ company asking a question.They answer you can find necessary thing on their page.They are suggesting I don’t know reading..

And I do not believe they will support their products for driver updates.After some time,they will will produce new thing and they will say we don’t support The product anymore and buy this.
Buy buy buy..

I also want to say a few things more.
There is a thing called ‘placebo effect’.
If you were able to detect/observe this effect on your own listening session(just one time), you can realize that placebo effect can be very STRONG effect.After that you begin to suspect from your judgements,and you think too much before using terms like “differences huge”-‘day and night’ on the forums..Maybe there is no difference at all..
I am saying for people reading this lines..

I have the Audio-GD R2R-2 DAC with Asynchronous Transfer Amanero Combo 384 USB.

As much as I love the sound of muy DAC, I still wonder if the Eitr is going to make it better. What is your honest opinion about it? Do you think that the Gen 5 in the Eitr is going to outperfom the Amanero of the DAC?

I know Eitr is cheap, but I cannot return it if I don’t like it because I live in Argentina, so I don’t want to buy snake oil.

Just to mention I have a pretty tranparent system, so I think I will be able to hear any difference, and I listen all the music streaming Tidal from my Notebook with USB connection to my DAC.